The present invention relates to electronic or battery operated devices, and more particularly to connector cables for electronic or battery operated devices.
Electronic or battery operated devices often include cables or wires (hereinafter connector cables) that supply power or data input to the device. Likewise, connector cables are often used to output power or data from the device. Strong and reliable connections between the device and the connector cables are important to the successful operation of the device. The connections must be substantially unaffected by the bending of the connector cables near the connections. Furthermore, the connections should not be broken simply by pulling on the connector cable. It is also desirable to seal the device and connections to prevent entry of any liquid or moisture that could damage the device or disrupt the working of the device.
Strong and reliable connections are extremely critical in the medical device industry where data acquisition devices are used to measure and monitor vital patient information, such as heart rate, respiratory rate, brain activity and the like. Care must be taken to ensure that patients, visitors, and medical personnel cannot accidentally break the connection by pulling or bending the connector cables. Likewise, the devices and their connections should be impervious to liquids that may be present in the clinical environment.
One common method of providing a cable connection that addresses all of the above-mentioned problems includes creating a permanent connection inside the housing of the device and then mechanically capturing the cable in the housing of the device so that the bending or pulling of the cable experienced outside of the device does not translate to the connection inside the housing. Various methods and designs can be used to effectuate such mechanical capture. To allow for servicing of the connector cable and connection, resealable gaskets can be used in conjunction with mechanical capturing to form a water-tight seal between the housing portions and the connector cable, thereby prohibiting liquids from entering the housing. If a resealable gasket is not used, the device must be discarded if the connector cable is damaged.
Instead of capturing the cable in the housing of the device, another possibility is to simply make the connection inside the housing and then overmold the entire assembly so that the device and connector cable become integral and non-separable. Ideally, pulling or bending the overmolded connector cable will only translate force into the overmolding of the device and not to the connection. Even though the overmolding creates a substantially water-tight seal, resealable gaskets must still be used between the housing portions and the connector cable to permit servicing. Should the connector cable or connection need repair or replacement, the overmolding must be removed and the housing opened. After the connection is repaired, the gasket is resealed and the assembly is overmolded. Again, if no resealable gasket is used, the device must be discarded if the connector cable is damaged.
Another option is to provide a sealed connector or socket as an entry point to the device. Instead of having the connector cables pass through the housing of the device, the connector cable can simply connect to a connector socket located on or in the housing. Since access to the inside of the housing is not needed, this type of connection configuration eliminates the need for a resealable gasket, and the housings can be ultrasonically welded together around the socket. However, this type of connection configuration must provide sufficient resistance to pullout forces to avoid accidental disengagement of the connector cable. This typically means using more expensive connectors, which adds to the cost of the device. Additionally, some form of seal is still required around the socket to prevent liquid from entering the device through or adjacent the socket. Connections of this type are subject to rigid patient safety requirements, such as those set forth by UL and IEC.
The different types of connections discussed above suffer from various problems. For the first two assemblies discussed (those with the connections inside the housing of the device), damage to the connector cable requires servicing or replacement of the entire device. To repair or replace a damaged connector cable, the device must be opened by a qualified service technician so that the technician can access the connection. Assuming the device is not ultrasonically welded together and can be opened, the housing portions must be carefully separated so as not to damage the resealable gasket. After the repair is complete, the housing must be carefully re-assembled to ensure that the gasket properly seals the device. If the gasket is damaged during repair, it must be replaced or the device must be discarded.
In the case of a unit having an integrally overmolded connector cable and device, the overmolding must first be removed before access to the connection can be achieved. This is also a job for a qualified service technician. After the repair is completed and the device is carefully re-assembled as described above, the unit must again be overmolded prior to returning to use.
For units having a socket directly on or in the housing, the problem becomes finding a connector that can adequately withstand the pullout forces. While these connectors are available, they are more expensive than common connectors. Furthermore, the design must still incorporate a seal between the socket and the device. This also adds to the cost of the device. Additionally, these units must be designed to meet the patient safety regulations discussed above.
The present invention solves the above-identified problems with prior art connection methods and provides a strong and reliable connection for an electronic or battery operated device. Cost is kept to a minimum as the connector cable utilizes a relatively inexpensive standard connector that plugs into a socket disposed just inside the ultrasonically welded housing. The connector end of the connector cable is overmolded with a soft thermoplastic that acts to provide bend and strain relief to the cable. The overmolding also incorporates an integral seal that prevents moisture from entering the device at the point of connection. A plastic locking clip snaps into place over the connection and seal to prevent the connector cable from pulling out of the device. The invention provides a low cost, easy to service, and safe alternative to the prior art connection methods.
More specifically, the present invention provides a connector cable assembly having an end adapted to be connected to a device. The connector cable assembly comprises a connector at the end of the connector cable, a wire electrically connected to the connector, an insulating cover at least partially surrounding the wire, an overmolding at least partially surrounding a portion of the insulating cover, a seal portion adjacent the overmolding, and a clip positionable over at least a portion of the overmolding. The clip includes an engaging member for securing the clip and the connector to the device. Preferably, the overmolding is made from a thermoplastic material that at least partially surrounds the connector. It is also preferred that the seal portion is integral with the overmolding.
The present invention also provides a method of connecting a connector cable to a device having a housing defining an opening and having therein a socket. The method comprises inserting a connector through the opening and into the socket, sealing the opening with a portion of the connector cable, sliding a clip over the connector cable, and releasably engaging the clip with the housing. Preferably, the steps of inserting the connector and sealing the opening occur substantially simultaneously.